A proton goes undflected in a crossed and magnetic field (the fields are perpendicular to each other) at a speed of `2.0X10^5 ms^(-1).` The velocity is perpendicular to both the fields. When the electric field is switched off, the proton moves along a circle of radius 4.0 cm. Find the magnitudes of the electric and the magnetic fields. take the mass of the proton `=1.6 X10^(-27)` kg.

Explanation

To solve the problem, we will follow these steps:

### Step 1: Understand the Forces Acting on the Proton
When the proton is moving in crossed electric and magnetic fields, it experiences two forces:
- The electric force \( F_e = qE \)
- The magnetic force \( F_m = qvB \)

Since the proton goes undeflected, these two forces must be equal in magnitude:
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